This application claims the benefit of Taiwan application Serial No. 094126622, filed Aug. 4, 2005, the subject matter of which is incorporated herein by reference.
1. Field of the Invention
The invention relates in general to a package module, and more particularly to the package module having a stacking platform.
2. Description of the Related Art
With the development of chip package technology, the recent industry has implemented the thin package by stacking the chips in one package. Also, another approach to improve the integration is to stack the chip packages to form a multi chip module (MCM), so called as “package in package”.
However, it is inevitable that some of chips in the conventional package module will be defective to some extent, particularly the chip bonded to the substrate with bared wires, so as to decrease the yield of package module and raise the production cost. As shown in
It is therefore an object of the present invention to provide a package module having a stacking platform. For steadily supporting the package in the module, a liquid encapsulating compound is used to be the stacking platform. Thus, the configurations and bonding positions of the gold wires in the module can be perfectly maintained.
The present invention achieves the objects by providing a package module comprising a first substrate, a first package, a second package and a molding compound. The first substrate has a first surface. The first package comprises a first chip and a liquid encapsulating compound. The first chip is disposed on the first substrate and electrically connected to the first substrate by a first gold wire. The liquid encapsulating compound encloses a second surface of the first chip and part of the first gold wire. A surface of the liquid encapsulating compound provides a platform, and the second package is disposed on the platform for package stacking. The molding compound encloses at least partial first surface of the first substrate, the first package and the second package.
The present invention achieves the objects by providing a method of fabricating a package module. First, a first substrate having a first surface is provided. A first chip is then disposed on the first substrate. The first chip is electrically connected to the first substrate by a first gold wire. Next, a liquid encapsulating compound is provided to enclose a second surface of the first chip and part of the first gold wire. The surface of the liquid encapsulating compound provides a platform. A second package is then disposed on the platform. A molding compound is provided to enclose at least partial first surface of the first substrate, the first package and the second package.
Other objects, features, and advantages of the present invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.
In the present invention, a package module having a stacking platform is disclosed. It is noted that the embodiments disclosed herein is used for illustrating the present invention, but not for limiting the scope of the present invention. Additionally, the drawings used for illustrating the embodiments and applications of the present invention only show the major characteristic parts in order to avoid obscuring the present invention. The drawings are diagrammatically show features of the present invention and their relation to other features and structures, and are not made to scale. Accordingly, the specification and the drawings are to be regard as an illustrative sense rather than a restrictive sense.
The second package 230 is disposed on the platform 251 provided by the upper surface of the liquid encapsulating compound 250. The second package 230 comprises a substrate 231, a chip 232 and a molding compound 234. The chip 232 is attached to the substrate 231 (such as by using epoxy), and wire bonded to the substrate 231 by the gold wires 233 to establish electrical connection. The chip 232 is electrically connected to the substrate 210 by the gold wires 235. The molding compound 234 encloses the substrate 231, the chip 232 and the gold wires 233. Besides, the molding compound 240 is formed to enclose the surface 212 of the substrate 210, the first package substrate 220 and the second package 230. Also, several solder balls 211 are attached to the bonding pads (not shown) on the bottom surface of the substrate 210.
Afterward, the receiving space at the central portion of the surface 226 created by the dam block 252 is filled with an encapsulation compound 253 having lower resistance to flow (such as silver epoxy), as shown in
Next, a second package 230 is attached to the platform 251 by silver epoxy 260, as shown in
In the package module 200 of the first embodiment, the liquid encapsulating compound 250 encloses the gold wires 224, 222, 225 and the chips 221, 223, and the surface of the liquid encapsulating compound 250 provides the platform 251 for disposing the second package 230. Compared to the conventional spacer 50 of
Besides, the platform 251 provided by the surface of the liquid encapsulating compound 250 is almost has the same top area as the chip 221. Compared to the conventional spacer 50, having a small top area and located near the left side of the chip 23, the platform 251 provides a larger supporting surface for disposing the second package 230. Also, the platform 251 touches the most bottom area of the second package 230, so that the second package 230 can be disposed on the platform 251 steadily. The conventional tilting problem of the second package 30 can be solved.
Moreover, the liquid encapsulating compound 25 having lower resistance to flow is adopted in the embodiment for protecting the chips 221 and 223. Compared to the conventional molding compound (reference number 40 in
The package module 300 also possesses the advantages as the package module 200, such as fully protect the gold wires in the first package 320, providing a larger supporting platform for the second package 330, and almost no air hole formed in the liquid encapsulating compound 350. Since the area of the platform 351 of the liquid encapsulating compound 350 is larger than the area of the platform 251 of the liquid encapsulating compound 250, the second package 330 disposed on the platform 351 is steadier than the second package 230 disposed on the platform 251.
According to the aforementioned description, the package module having a stacking platform can fully protect the chips and the gold wires. Besides, the liquid encapsulating compound (250/350) enclosing the first package (220/320) provides a large supporting area for disposing the second package (230/330) steadily. Also, the platform of the invention can be fabricated using a simple process, which is cost saving. The conventional problem of gold wire crashed by the tilted package can be solved since the gold wires of the invention are fully protected by the liquid encapsulating compound. Thus, the yield of the package module of the invention is increased, and the electrical test of each package in the package module of the invention shows a satisfactory result.
While the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Number | Date | Country | Kind |
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94126622 | Aug 2005 | TW | national |